diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -2093,7 +2093,7 @@
   /// Retrieve the set of partial specializations of this class
   /// template.
   llvm::FoldingSetVector<ClassTemplatePartialSpecializationDecl> &
-  getPartialSpecializations();
+  getPartialSpecializations() const;
 
   ClassTemplateDecl(ASTContext &C, DeclContext *DC, SourceLocation L,
                     DeclarationName Name, TemplateParameterList *Params,
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -403,7 +403,7 @@
 }
 
 llvm::FoldingSetVector<ClassTemplatePartialSpecializationDecl> &
-ClassTemplateDecl::getPartialSpecializations() {
+ClassTemplateDecl::getPartialSpecializations() const {
   LoadLazySpecializations();
   return getCommonPtr()->PartialSpecializations;
 }